The present invention relates to hand tools and, more specifically, to an adjustable wrench.
When operating a conventional adjustable wrench 100, as shown in FIG. 1, the user may hold the adjustable wrench 100 in horizontal, and then rotates the adjusting worm 101 with the thumb to move the adjustable jaw 102 to the desired position. In order to let the adjustable jaw 102 be smoothly moved along the slide rails 104 of the fixed jaw (not shown), a clearance c is left between the slide rails 103 of the adjustable jaw 102 and the slide rails 104 of the fixed jaw. However, the moment produced by the weight w of the adjustable jaw 102 forces the adjustable jaw 102 to incline in one direction, thereby causing one slide rail 103 of the adjustable jaw 102 to attach one slide rail 104 of the fixed jaw. When moving the adjustable jaw 102 at this time, the rails 103 and 104 are rubbed against each other, causing an unstable movement of the adjustable jaw 102. A conventional method of eliminating the aforesaid problem is to reduce the clearance c between the adjustable jaw and the fixed jaw. For example, ASME (The American Society of Mechanical Engineers) B107.8M-1996 defines that the clearance of the adjustable jaw must be as low as within 0.3 mmxcx9c0.47 mm. ISO (International Standard Organization) 6786-1982(E) defines that the clearance of the adjustable jaw must be as low as within 0.25 mmxcx9c0.36 mm when applying a slight side pressure on the adjustable jaw. The definitions of ISO and ASME do not stop the occurrence of friction between the slide rails of the adjustable jaw and the slide rails of the fixed jaw, i.e., these definitions do not eliminate the aforesaid problem.
It is one object of the present invention to provide an adjustable wrench, which eliminates friction during movement of the adjustable jaw relative to the fixed jaw.
It is another object of the present invention to provide an adjustable wrench, which prevents the adjustable jaw from trembling in its moving direction when adjusted to the desired position.
To achieve the objects of the present invention, an adjustable wrench is provided comprised of a frame, having a handle, a fixed jaw and a track at one end of the handle. An adjusting worm pivoted to the frame for free rotation. An adjustable jaw mounted in the track and meshed with the adjusting worm and moved relative to the fixed jaw upon rotating the adjusting worm. Two spaces defined at two sides of the adjustable jaw within the track of the frame. At least one packing device provided in each of two spaces for preventing the friction between the side rails of the adjustable jaw and the side rails of the fixed jaw.